Liftoff!

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After shrugging off some delays due to clouds, Ares I-X has lifted off into the Florida sky and done what it was designed to do: lift off, test the flight software, perform a separation maneuver, and test the recovery system. This is a great day for the Ares I-X Mission Management Office, and a first step toward NASA’s next generation of human spaceflight. More details on the data will be coming out over the next several days, weeks, and months.

Triboelectrification Questions? Try This.

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An earlier blog post attempted to answer questions about triboelectrification. Since there are still a few questions floating around we’re reposting it for those who missed it on the first go-round.

Enjoy.

Flight Rules and Triboelectrification (Whatthe Heck is That?)
 
The skies look clear except for some high clouds, there’s no rain in theimmediate forecast, so why might a rocket not launch? The answer is somethingcalled triboelectrification. While this isn’t a word you encounter every day,you might experience it if you walk across a dry carpet or brush up against acat and then touch a metal surface: it’s static.
 
In the case of Ares I-X, flying through high-level clouds can generate“P-static” (P for precipitation), which can create a corona of static aroundthe rocket that interferes with radio signals sent by or to the rocket. Thiswould create problems when the rocket tries to transmit data down to the groundor if the Range Safety Officer at Cape Canaveral Air Force Station needed tosend a signal to the flight termination system. Until the 45th Space Wing andobserver aircraft indicate that the skies are clear, Ares I-X will wait themout. 

Why a Four-Hour Launch Window?

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One question thatcomes up a lot is why Ares I-X has a four-hour launch window. After all, unlikethe Space Shuttle, it doesn’t have to rendezvous with the Space Station, sowhat’s the challenge? Actually, there are several.

First, the Eastern Range typically allots 4-hour launch windows. Given theduration of Ares I-X (about seven minutes from liftoff until the final piecessplash down), more time is not required. As was demonstrated on the firstlaunch attempt, the rocket can be reset quickly, so four hours was consideredplenty of time to wait out weather and technical challenges.
 
Next, there are human limitations. Console operators in the Launch ControlCenter must be at their consoles at least 7 hours before the planned launch.When you add the 4-hour window this means that operators may have to be onstation for 11 hours before launch. There is also a lot of work to do afterlaunch or after a scrub.

Additionally, anyone familiar with Florida weather understands that windstypically pick up later in the day as the atmosphere heats up and interactswith evaporation from the ocean. Central Florida’s “afternoon thunderstorms”produce a terrific number of lightning strikes. High winds are a problem forany launch. Because of its experimental nature, Ares I-X has very conservativewind constraints—20 knots (nautical miles per hour—about 23 statute miles perhour) as opposed to the Space Shuttle, which can fly in winds up to 30 knots(34.5 miles per hour).

A 4-hour window, gives the teamthe ability to complete all the preparation work, wait for the rightcombination of winds, weather and clouds and then go. Following the LCCguidelines gives Ares I-X the best chance to collect the important data that weneed for next exploration steps we take.

 

Whatever Happened to the Five-Hole Probe?

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Remember that probeon the top of the rocket? It’s still being watched carefully today, and notjust because of its hard-to-remove cover.
 
As we noted yesterday, the five-hole probe is a very important set of sensorsfor collecting aerodynamic data during the flight. It remained covered whileAres I-X was rolled out to the launch pad and just prior to launch because theavionics team did not want water, bugs, bird messes, or other debris getting onor in the sensors. Inside the five holes is a diaphragm of flexible materialagainst which air vibrates to produce data. If water or foreign object debris(FOD) gets onto the diaphragm, there is a risk that the data from the sensorscould be harder to interpret after the flight. Once the Ground Operations teamremoved the cover, there is no way to put it back on short of rolling therocket back into the Vehicle Assembly Building. The I-X team knew this mighthappen, but now that the cover is off, what next? Just to add to the challenge,Cape Canaveral expected (and got) an inch and a half of rain on Tuesday night.
 
What NASA did was take a spare five-hole probe out to the pad, put it on thefixed service structre and gave it a similar exposure to rain as the flighthardware. The spare unit was tested before and after the rain to determine itseffects on the sensors’ behavior. In this way, NASA will be able to account forany changes in sensor measurements due to water on the sensor and use thatinformation to interpret the data after the flight. This is just one of manylessons the Ares team is learning as it continues testing on the Ares I-Xrocket.

Not Today

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Well, the weather didn’t cooperate with us today. Winds andclouds we’re outside of our allowable limits, so we’re packing it in and we’lltry again tomorrow. Launch window opens at 8:00 EDT on Oct. 28 and continuesthrough until noon.

Launch coverage onNASA TV begins at 5 am EDT – www.nasa.gov/ntv 

When is a Rocket Launch Like a Soap Opera?

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Drama can take many forms. A good drama has suspense, sudden pitfalls, unexpected turns, and emotional intensity. You don’t need to go to the movies for that. Today, you can just turn on NASA TV and watch the challenges experienced by the Ares I-X flight test. Since the originally scheduled launch time of 8 a.m. Eastern Time, we’ve seen holds due to weather, trouble pulling off a cover for a sensor on top of the rocket, a ship sailing into the splashdown portion of the range, and then another last-minute weather delay due to clouds.
 
Like any good drama, we enjoy a great sigh of relief when all comes right in the end. Keep watching, the adventure continues.

The Pointy End of the Rocket

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There’s a running joke around NASA that the mostimportant thing about rocket travel is that “the pointy end goes up.” Thatseems simple enough—and that’s what we expect Ares I-X to do today. But haveyou ever wondered what is ON the pointy end of the rocket? You might be surprised.
 
Rather than an actual point or smooth, aerodynamic surface, the very top of theAres I-X rocket is capped by an instrument called the “five-hole probe.” As itsname suggests, this instrument has five holes on its conical point, which takein air during flight. The probe is actually a set of sensors that collectsaerodynamic data, including total air pressure, static air pressure, angle ofattack, and other measures that verify how well the vehicle is beingcontrolled—one of the primary objectives of the test.

Because of the importance of this sensor, the five-hole probe is keptunder a protective cover, which will be removed by someone standing on top ofthe launch gantry and pulling it off with a lanyard. The cover will be removedabout 45 to 50 minutes before launch time. Once the cover is off, the five-holeprobe will be ready to slice through the air and make its contribution to theflight test…pointy end up, of course.

Flight Rules and Triboelectrification (What the Heck is That?)

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The skies look clear except for some high clouds,there’s no rain in the immediate forecast, so why might a rocket not launch?The answer is something called triboelectrification. While this isn’t a wordyou encounter every day, you might experience it if you walk across a drycarpet or brush up against a cat and then touch a metal surface: it’s static.
 
In the case of Ares I-X, flying through high-level clouds can generate“P-static” (P for precipitation), which can create a corona of static aroundthe rocket that interferes with radio signals sent by or to the rocket. Thiswould create problems when the rocket tries to transmit data down to the groundor if the Range Safety Officer at Cape Canaveral Air Force Station needed tosend a signal to the flight termination system. Until the 45th Space Wing andobserver aircraft indicate that the skies are clear, Ares I-X will wait themout. 

The Pulse of the Public

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The NASAEdge <http://www.nasa.gov/nasaedge> team is interviewing spectators at the Ares I-X launch site to take thepulse of the public and ask them what they think of the launch. Here are someof the answers they’ve gotten so far.
 
Ares I-X and the History of NASA
http://www.youtube.com/watch?v=SVa2C1HuoUE

Graduation Day
http://www.youtube.com/watch?v=hDR19pQS1ZU&feature=channel

What Does Ares I-X Mean?
http://www.youtube.com/watch?v=B0AIHfPOY0k&feature=channel
 
How Far Did You Travel to See the Launch?
http://www.youtube.com/watch?v=aVewk4hxYVA
 
Stay tuned to NASAEdge for the latest viewer responses.

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